Police told The Bismarck Tribune that the man, who was not identified, was offering grass clippings for sale, which could have been mistaken for marijuana, in a parking lot in Bismarck. Police were called by a woman who said he tried to sell to her just before 1 a.m., according to the Tribune.

According to an affidavit obtained by MyNDNews.com, two additional witnesses told police that the man was trying to sell the grass to them as well.

“At first, the suspect claimed it was marijuana, then said it was synthetic,” the news site reported. “After the witnesses refused to buy, he said, ‘Just kidding, it’s grass.’”

KFYR reported that the man agreed to let police search him. Officers said they found a bag in his pocket containing the grass clippings.

Police arrested the man on a charge of intent to deliver an imitation controlled substance, according to the Tribune.